From 044a6e08c2aee23ef18c60a036e01d3b77168830 Mon Sep 17 00:00:00 2001
From: sheaf <sam.derbyshire@gmail.com>
Date: Thu, 20 Mar 2025 19:21:01 +0100
Subject: [PATCH] LLVM: fix typo in padLiveArgs
This commit fixes a serious bug in the padLiveArgs function, which
was incorrectly computing too many padding registers. This caused
segfaults, e.g. in the UnboxedTuples test.
Fixes #25770
Fixes #25773
---
compiler/GHC/CmmToLlvm/Base.hs | 2 +-
testsuite/tests/llvm/should_run/T25770.hs | 15 +++++++++++++++
testsuite/tests/llvm/should_run/T25770.stdout | 1 +
testsuite/tests/llvm/should_run/all.T | 1 +
4 files changed, 18 insertions(+), 1 deletion(-)
create mode 100644 testsuite/tests/llvm/should_run/T25770.hs
create mode 100644 testsuite/tests/llvm/should_run/T25770.stdout
diff --git a/compiler/GHC/CmmToLlvm/Base.hs b/compiler/GHC/CmmToLlvm/Base.hs
index b56d4ed9be5..4f9d854add4 100644
--- a/compiler/GHC/CmmToLlvm/Base.hs
+++ b/compiler/GHC/CmmToLlvm/Base.hs
@@ -237,7 +237,7 @@ padLiveArgs platform live =
text ") both alive AND mapped to the same real register: " <> ppr real <>
text ". This isn't currently supported by the LLVM backend."
go (cu@(GlobalRegUse c _):cs) f
- | fpr_num c == f = go cs f -- already covered by a real register
+ | fpr_num c == f = go cs (f+1) -- already covered by a real register
| otherwise = ctor f : go (cu:cs) (f + 1) -- add padding register
fpr_ctor :: GlobalRegUse -> Int -> GlobalRegUse
diff --git a/testsuite/tests/llvm/should_run/T25770.hs b/testsuite/tests/llvm/should_run/T25770.hs
new file mode 100644
index 00000000000..5e1b1c72e9e
--- /dev/null
+++ b/testsuite/tests/llvm/should_run/T25770.hs
@@ -0,0 +1,15 @@
+{-# LANGUAGE UnboxedTuples, MagicHash #-}
+
+module Main where
+
+import GHC.Exts
+
+tuple6 :: () -> (# Float#, Double#, Float#, Double#, Float#, Double# #)
+tuple6 _ = (# 1.0#, 2.0##, 3.0#, 4.0##, 5.0#, 6.0## #)
+{-# NOINLINE tuple6 #-}
+
+main :: IO ()
+main =
+ case tuple6 () of
+ (# _, _, _, _, _, d' #) ->
+ print (D# d')
diff --git a/testsuite/tests/llvm/should_run/T25770.stdout b/testsuite/tests/llvm/should_run/T25770.stdout
new file mode 100644
index 00000000000..e0ea36feef6
--- /dev/null
+++ b/testsuite/tests/llvm/should_run/T25770.stdout
@@ -0,0 +1 @@
+6.0
diff --git a/testsuite/tests/llvm/should_run/all.T b/testsuite/tests/llvm/should_run/all.T
index 94c19fc6050..e6c6d84e2e3 100644
--- a/testsuite/tests/llvm/should_run/all.T
+++ b/testsuite/tests/llvm/should_run/all.T
@@ -12,6 +12,7 @@ setTestOpts(f)
def ignore_llvm_and_vortex( msg ):
return re.sub(r".* is not a recognized processor for this target.*\n",r"",msg)
+test('T25770', [normal, normalise_errmsg_fun(ignore_llvm_and_vortex)], compile_and_run, [''])
test('T22487', [normal, normalise_errmsg_fun(ignore_llvm_and_vortex)], compile_and_run, [''])
test('T22033', [normal, normalise_errmsg_fun(ignore_llvm_and_vortex)], compile_and_run, [''])
test('T25730', [req_c, unless(arch('x86_64'), skip), normalise_errmsg_fun(ignore_llvm_and_vortex)], compile_and_run, ['T25730C.c'])
--
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